In this video from Cyberchase, Bianca is babysitting infant twins. As she tries to give each twin the same amount of liquid baby formula, she discovers that all the baby bottles are different shapes. Learn how she finds two that hold the same amount. In the accompanying classroom activity, students estimate which of four empty containers has the greatest capacity and then determine which one does by measuring actual volume. This resource is part of the Math at the Core: Middle School Collection.